1. Field of the Invention
This invention relates to an improvement in the blood dialyzing apparatus and, more particularly, to a blood dialyzing apparatus comprising at least one bundle of semi-permeable hollow filaments and a cylindrical housing positioning said bundle of filaments and having a large length to inside diameter ratio.
2. Description of the Prior Art
Blood dialyzers employing hollow filaments are well known as artificial kidneys and have been available in a number of configurations and constructions. These dialyzers may be generally classified into those employing a cylindrical housing and those employing an oblong housing. The dialyzer using a cylindrical housing can be manufactured more easily and a large majority of blood dialyzers available today are of this type.
In designing a cylindrical blood dialyzer, its structural parameters such as the ratio of length to inside diameter have heretofore been selected with emphasis on the relationship of blood and dialysate flows. Thus, to prevent clotting and hemolysis, the blood is desirably treated under as mild conditions as possible. Thus, excessively highly flow rates and high pressures of blood have to be avoided and it has, therefore, been thought that the cross-sectional area of the hollow filaments' lumens is preferably large. Thus, the conventional cylindrical blood dialyzer includes a large number of hollow filaments and its housing has a comparatively large diameter with respect to its length. Thus, the ratio of length to inside diameter of the housing is within about 3 to 5.5.